“Oral dysbiosis” is a microbiology term for having an imbalance in the microbial community that inhabits the oral cavity…in other words, the number of potentially harmful microbes is higher than we would like to see. This strongly correlates with dental disease in humans, dogs, and cats.
What can cause it? Drivers of oral dysbiosis are diet, age, lack of exercise, exposure to antibiotics, some medications and an alteration of pet’s health status (particularly having to do with saliva production and liver function).
It can also be caused by the introduction of dental pathogens (microbes known to cause dental disease). A single kind of microbe can disturb the balance in a microbial community. A group showed that healthy animals, after they are exposed to a particularly harmful bacteria called Porphyromonas gingivalis, can develop oral dysbiosis and start showing signs of gingivitis. 
A hallmark of oral dysbiosis is the loss of microbial diversity within the oral cavity. It is the diverse microbes that keep pets healthy by helping to balance the immune system, keep the gum tissue healthy and limit the overgrowth of harmful bacteria and fungus. Microbes such as Lactic Acid bacteria are known to be protective, if fed the appropriate nutrients (they can regulate healthy immune balance and promote healthy barrier functions).
In lower gut and skin microbiome research, loss of diversity strongly correlates with an increase in inflammation. [2,3] Similarly, recent work has shown that oral dysbiosis, particularly below the gumline, can upset the immune system and can lead to an accumulation of white blood cells, called neutrophils (neutrophils make pus), into the affected tissue. 
A second hallmark of oral dysbiosis is the increased presence (burden) of pathogenic microbes, such as Porphyromonas sp., Tannerella sp., Treponema sp., and/or abnormally high levels of commensal microbes such as Actinomyces sp. or Fusobacterium sp. [4-6] These pathogenic microbes are crafty and can invade the gum tissue and gain access into the body to cause inflammation elsewhere. They also often gain the upper hand against the immune system and have mechanisms that can “evade” it, so that they often persist once they establish colonization.
If you have read this much, you are probably scared to know what lurks in your pet’s mouth!
The good news is that we are experts in this topic and are working on building a line of products for daily rehabilitation of oral dysbiosis in pets. Our goal is to go beyond conventional products to stop dysbiosis in its tracks. How do we do this? We use prebiotics to grow a diverse population of beneficial microbes in your pet’s mouth while using a blocking fiber to limit sugar-based growth of the harmful microbes. The best part is that our approach works directly on the bacteria, not on your pet.
Dr. Stein holds a Ph.D. in Microbiology from the University of California at Berkeley where she studied signaling pathways involved in stress response and community development in bacteria and received her B.S. in Microbiology and Immunology at the University of Iowa where she studied the interaction between M. tuberculosis and innate immune cells. She founded Primal Health, LLC to focus on improving the quality of life and longevity of both humans and animals by producing innovative, consumable and safe dental hygiene products. Their patented prebiotic technology centers on re-engineering disease-causing bacterial biofilms into those that are health-promoting.